U.S. patent number 8,227,532 [Application Number 13/209,480] was granted by the patent office on 2012-07-24 for non-dripping flame retarding masterbatch, composition and process for preparing the same and flame retarding article containing the same.
This patent grant is currently assigned to Taiwan Textile Research Institute. Invention is credited to Wei-Ming Chen, Nai-Yun Liang, Sheng-Jen Lin, Wei-Peng Lin.
United States Patent |
8,227,532 |
Lin , et al. |
July 24, 2012 |
Non-dripping flame retarding masterbatch, composition and process
for preparing the same and flame retarding article containing the
same
Abstract
Disclosed herein are methods for preparing non-dripping flame
retarding masterbatches and filamentous non-dripping flame
retarding materials. First, an admixture including a flame
retardant, a crosslinking agent, a thermoplastic polymer, and a
dispersing agent is prepared, and then a crosslinking initiator is
added into the admixture to form a composition which is then
compounded and pelletized to obtain the non-dripping flame
retarding masterbatch. The resultant non-dripping flame retarding
masterbatch is suitable for use in a spinning process to obtain
filamentous non-dripping flame retarding materials.
Inventors: |
Lin; Sheng-Jen (Taoyuan,
TW), Chen; Wei-Ming (Tu-Chen, TW), Liang;
Nai-Yun (Taipei, TW), Lin; Wei-Peng (Sijhih,
TW) |
Assignee: |
Taiwan Textile Research
Institute (Tu-Chen, Taipei Hsien, TW)
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Family
ID: |
43898966 |
Appl.
No.: |
13/209,480 |
Filed: |
August 15, 2011 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110301258 A1 |
Dec 8, 2011 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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12648083 |
Dec 28, 2009 |
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Foreign Application Priority Data
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Oct 28, 2009 [TW] |
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98136535 A |
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Current U.S.
Class: |
524/115; 522/76;
524/140; 264/13 |
Current CPC
Class: |
C08L
23/12 (20130101); C08K 5/0066 (20130101); C08J
3/226 (20130101); C08K 3/32 (20130101); C08K
5/0025 (20130101); C08K 5/0066 (20130101); C08L
23/10 (20130101); C08K 5/0066 (20130101); C08L
67/02 (20130101); C08K 5/0066 (20130101); C08L
27/06 (20130101); C08K 5/0066 (20130101); C08L
77/00 (20130101); C08L 23/12 (20130101); C08L
2666/02 (20130101); C08J 2477/00 (20130101); C08J
2467/00 (20130101); C08J 2427/00 (20130101) |
Current International
Class: |
C08G
18/77 (20060101) |
Field of
Search: |
;524/115 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lee; Doris
Attorney, Agent or Firm: Thomas, Kayden, Horstemeyer &
Risley, LLP
Parent Case Text
RELATED APPLICATIONS
This application is a divisional application of co-pending U.S.
application Ser. No. 12/648,083 filed Dec. 28, 2009, the entirety
of which is incorporated herein by reference.
Claims
What is claimed is:
1. A method for preparing a non-dripping flame retarding fiber, the
method comprising the steps of: admixing a flame retardant in an
amount of about 1.0 wt % to about 15.0 wt %, a crosslinking agent
in an amount of about 0.1 wt % to about 1.5 wt %, a nylon polymer
in an amount of about 76.5 wt % to about 99.5 wt %, and a
dispersing agent in an amount of about 0.1 wt % to about 5.0 wt %
to form a admixture; adding a crosslinking initiator in an amount
of about 0.01 wt % to about 2.0 wt % into the admixture to form a
composition for compounding; compounding the composition for about
1-20 minutes at a compounding temperature of about 220-270.degree.
C. to obtain a compounded product; pelletizing the compounded
product to obtain a non-dripping flame retarding masterbatch; and
spinning the non-dripping flame retarding masterbatch to obtain the
non-dripping flame retarding fiber having an elongation of at least
45%.
2. The method of claim 1, further comprising treating the
non-dripping flame retarding masterbatch with a UV curing process
whereby improving the non-dripping efficacy of the flame retarding
fiber.
3. The method of claim 1, wherein the flame retardant is
polyphosphate or ammonium polyphosphate.
4. The method of claim 1, wherein the crosslinking agent is diallyl
phthalate, diallyl succinate, N,N'-diallyltartramide,
triacryloylhexahydro-1,3,5-triazine, triallylamine, triallyl
trimesate, triallyl cyanurate, triallyl isocyanurate, or
triallyl-ammoniumcyanurate.
5. The method of claim 1, wherein the crosslinking initiator is
potassium persulfate, azobisisobutyronitrile, or benzyl dimethyl
ketal.
6. The method of claim 1, wherein the dispersing agent is selected
from a group consisting of C15-38 alkanes, C15-38 esters, C15-38
organic acids, and a mixture thereof.
7. The method of claim 1, wherein the nylon polymer is nylon 6,
nylon 6.6, or nylon 6.10.
8. The method of claim 1, wherein the flame retardant has a
diameter of about 1-10 .mu.m.
Description
BACKGROUND
1. Field of Invention
The present disclosure relates to flame retarding materials. More
particularly, the present disclosure relates to non-dripping flame
retarding materials.
2. Description of Related Art
Flame retardants are widely used in plastic and textile materials
so as to bestow combustion-inhibiting or flame-resistant properties
to the final products. Depending on the principal component, flame
retardants can be categorized in to halogenated flame retardants,
phosphorus-containing flame retardants, phosphorus and nitrogen
containing flame retardants and inorganic flame retardants.
The principal component of the halogenated flame retardants is
halocarbon such as polychlorinated biphenyl, chlorinated paraffin,
polybrominated biphenyl, and polybromophenyl ether. Halogenated
flame retardants are known to exhibit good flame-retarding efficacy
and are highly compatible with plastic materials. Moreover, the
halogenated flame retardants would not significantly affect the
inherent properties of the plastic materials, and thus would not
jeopardize the mechanical properties of the final products.
Therefore, halogenated flame retardants are widely used in various
plastic and textile products in the early days. During combustion,
however, the halogenated flame retardants may produce black smokes
that are sometimes corrosive; more particularly, some halogenated
flame retardants may produce carcinogenic substances. In view of
the safety concerns to the environment and human health, most
halogenated flame retardants are banned for use in textile
products, with only a small portion of halogenated flame retardants
are allowed in plastic materials.
Common examples of phosphorus-containing flame retardants may
include, but are not limited to red phosphorus, polyphosphate and
ammonium polyphosphate. The phosphorus content of the red
phosphorus may be up to 100%, and hence, theoretically, red
phosphorus should be the most effective one among all the
phosphorus-containing flame retardants. However, the appearance of
the red phosphorus is usually black or red which together with its
poor compatibility with plastic materials and poor processability
limit its application in the plastic and textile fields. On the
other hand, polyphosphate and ammonium polyphosphate are widely
used in the textile field as flame retardants. However, in order to
exhibit satisfactory fire retarding efficacy, the required content
of such fire retardants is as high as 30 wt % which may not only
increase the manufacturing cost but also decrease the spinnability
of the material. In addition, phosphorus-containing flame
retardants may cause dripping effect during combustion.
Phosphorus and nitrogen containing flame retardants, also known as
intumescent fire retardants, are halogen-free flame retardants.
Examples of intumescent fire retardants are ammonium polyphosphate,
melamine (trimeric cyanamide) and pentaerythritol. The phosphorus
and nitrogen containing flame retardants would increase the carbon
source and acid source and swell upon heating. In addition, they
produce less smoke and substantially no toxic gases during burning.
However, the processability and weather resistance of the
phosphorus and nitrogen containing flame retardants are less
satisfactory, and hence, the properties thereof may change under
the influences of the weather and environment. Moreover, phosphorus
and nitrogen containing flame retardants may be separated from the
matrix material, for example, while being damped or hydrolyzed.
Inorganic flame retardants include antimony trioxide, magnesium
hydroxide, aluminium hydroxide, and zinc borate. These materials
produce less smoke during combustion, and usually release
substances such as water and carbon dioxide that are more
environmentally friendly. However, the flame retarding efficacy of
such inorganic materials is not as desirable as the organic fire
retardants. Hence, the inorganic materials should be added in a
substantially great amount to bestow a satisfactory flame retarding
efficacy to the final product material. Besides, such inorganic
materials are poorly compatible with thermoplastic materials such
as resins, and hence they tend to aggregate within the
thermoplastic materials.
In sum, various problems are experienced while using the flame
retardants in the textile field. Such problems are, for example,
poor in processability, washing fastness and mechanical properties.
Regarding the finished flame retarding textiles, the textiles may
not possess desirable transparency. Also, the textiles, during
combustion, may not exhibit satisfactory flame retarding efficacy
and may cause dripping effect.
In view of the foregoing, there exits an urgent need in the related
field to provide a novel flame retarding materials that possess
both desirable processing characteristics and flame retarding
efficacy.
SUMMARY
The following presents a simplified summary of the disclosure in
order to provide a basic understanding to the reader. This summary
is not an extensive overview of the disclosure and it does not
identify key/critical elements of the present disclosure or
delineate the scope of the present disclosure. Its sole purpose is
to present some concepts disclosed herein in a simplified form as a
prelude to the more detailed description that is presented
later.
In one aspect, the present disclosure is directed to a composition
for preparing a non-dripping flame retarding masterbatch. The
non-dripping flame retarding masterbatch thus-obtained exhibits
both flame retarding and non-dripping capabilities. Moreover, the
amount of the flame retardant(s) in such composition is less than
those contained in the conventional compositions, therefore
reducing the production cost and improving the spinnability and
other mechanical properties of the masterbatch.
According to one embodiment of the present disclosure, the
composition comprises: about 0.1-15.0 wt % flame retardant, about
0.1-1.5 wt % crosslinking agent, about 76.5-99.5 wt % thermoplastic
polymer, about 0.01-2.0 wt % crosslinking initiator, and about
0.1-5.0 wt % dispersing agent.
In another aspect, the present disclosure is directed to a method
for preparing a non-dripping flame retarding masterbatch.
Generally, the composition(s) used to preparing the non-dripping
flame retarding masterbatch in accordance with such method may fall
within the scope of the composition presented in the
above-mentioned aspect/embodiment(s).
According to one embodiment of the present disclosure, the method
comprises the steps as follows. About 0.1 to about 15.0 wt % flame
retardant, about 0.1 to about 1.5 wt % crosslinking agent, about
76.5 to about 99.5 wt % thermoplastic polymer, and about 0.1 to
about 5.0 wt % dispersing agent are admixed to form an admixture.
Thereafter, about 0.01 to about 2.0 wt % crosslinking initiator was
added into the admixture to form a composition for compounding. The
composition is compounded to melt the thermoplastic polymer whereby
the melted thermoplastic polymer is cross-linked by the
crosslinking agent, and the retarding agent is dispersed in the
cross-linked thermoplastic. Generally, the compounding step is
performed for about 1-20 minutes, and a compounding temperature is
about 220-270.degree. C. Afterwards, the cross-linked thermoplastic
having the retarding agent dispersed therein is pelletized to
obtain the non-dripping flame retarding masterbatch.
In yet another aspect, the present disclosure is directed to a
non-dripping flame retarding material.
According to embodiments of the present disclosure, the
non-dripping flame retarding material comprises a crosslinked
thermoplastic polymer and a fire retardant dispersed within the
thermoplastic polymer, wherein the weight ratio of the crosslinked
thermoplastic polymer to the fire retardant is about 5:1 to 996:1.
Comparing with conventional flame retarding materials, such
non-dripping flame retarding material contains less flame retardant
while exhibits adequate flame retarding capability.
Many of the attendant features will be more readily appreciated as
the same becomes better understood by reference to the following
detailed description considered in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The present description will be better understood from the
following detailed description read in light of the accompanying
drawings, wherein:
FIG. 1A is a photo illustrating the after-burnt appearance of a
pure nylon material;
FIG. 1B is a photo illustrating the after-burnt appearance of a
nylon material according to one example of the present
disclosure;
FIG. 2A is a photo illustrating the after-burnt appearance of a
pure polyester material;
FIG. 2B is a photo illustrating the after-burnt appearance of a
polyester material according to another example of the present
disclosure;
FIG. 3A is photo illustrating a textile obtained by spinning the
non-dripping flame retarding masterbatch of one embodiment of the
present disclosure; and
FIG. 3B is a photo illustrating the after-burnt appearance of the
fabric of FIG. 3A.
DETAILED DESCRIPTION
The detailed description provided below in connection with the
appended drawings is intended as a description of the present
examples and is not intended to represent the only forms in which
the present example may be constructed or utilized. The description
sets forth the functions of the example and the sequence of steps
for constructing and operating the example. However, the same or
equivalent functions and sequences may be accomplished by different
examples.
Factors to be taken into account while manufacturing a flame
retarding material may include the compatibility between the flame
retardant and the thermoplastic material, the effects the flame
retardant may impose on the mechanical properties of the
thermoplastic material, flame retarding efficacy of the flame
retarding material, the processability of the flame retarding
material, the price/performance ratio of the flame retarding
material, and safety concerns to the environment and human health
during the processing and/or burning of the flame retarding
material.
In view of the foregoing and other factors, a first aspect of the
present disclosure is directed to a composition for preparing a
non-dripping flame retarding masterbatch. Generally, the
composition for preparing the non-dripping flame retarding
masterbatch comprises a flame retardant, a crosslinking agent, a
thermoplastic polymer, a crosslinking initiator, and a dispersing
agent. Examples and proportions of the aforementioned constituents
are provided hereinafter.
According to embodiments of the present disclosure, the composition
may employ any suitable flame retardants. However, most halogenated
flame retardants may cause negative effects to the environment and
human health; hence, a non-limiting example of the flame retardant
may be halogen-free flame retardants.
Moreover, phosphorus-containing flame retardants are frequently
used flame retarding textiles. Therefore, in one optional
embodiment, phosphorus-containing flame retardants may be used.
Examples of phosphorus-containing flame retardants include, but are
not limited to polyphosphates and ammonium polyphosphates.
Conventional masterbatches usually comprise 20-30 wt % flame
retardants, such as phosphorus-containing or other flame
retardants, so as to provide the masterbatches and/or the resultant
flame retarding textiles with a desirable flame retarding efficacy.
Nevertheless, the composition according to embodiments of the
present disclosure comprises a flame retardant present in an amount
of about 0.1-15 wt %, while the resultant masterbatch may still
exhibit an adequate flame retarding efficacy. In some embodiments,
the flame retardant is in an amount of about 5-15 wt %.
Furthermore, the flame retarding materials of the present
disclosure have no observable melt dripping upon exposure to
flame.
Specifically, the weight percent of the flame retardant of the
total composition may be about 0.1, 0.2, 0.5, 1.0, 1.5, 2.0, 2.5,
3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 0.0, 85, 9., 9.5,
10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, or
15.0%.
According to optional embodiments of the present disclosure, the
flame retardant used may be in a form of micrometer scale powder.
Hence, the flame retardant may be more evenly dispersed within the
thermoplastic polymer. For example, the diameter of the flame
retardant powder may be about 1-10 .mu.m, such as about 1, 2, 3, 4,
5, 6, 7, 8, 9, or 10 .mu.m.
According to embodiments of the present disclosure, the
crosslinking agent may be a diallyl compound or a triallyl
compound.
Illustrative examples of diallyl compounds include, but are not
limited to, diallyl phthalate (DAP), diallyl succinate (DASu), and
N,N'-diallyltartramide (DATD).
Illustrative examples of triallyl compounds include, but are not
limited to, triallylamine, triacryloylhexahydro-1,3,5-triazine
(TAT), triallyl trimesate (TAM), triallyl cyanurate (TAC), triallyl
isocynaurate (TAIC), and triallyl-ammoniumcyanurate. For example,
TAT is used in an example provided hereinafter.
According to various embodiments of the present invention, the
weight percent of the crosslinking agent of the composition for
preparing a non-dripping flame retarding masterbatch is about 0.1%
to about 1.5%. In some embodiments, the crosslinking agent is in an
amount of about 0.5 wt % to about 1.5 wt %. Specifically, the
weight percent of the crosslinking agent of the total composition
may be about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1,
1.2, 1.3, 1.4, or 1.5%.
The addition of the crosslinking initiator in the composition may
facilitate the crosslinking reaction. The weight percent of the
crosslinking agent of the composition for preparing a non-dripping
flame retarding masterbatch is about 0.01% to about 2%; more
specifically, about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08,
0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2,
1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2%.
The choice of the crosslinking initiator often depends on the
crosslinking agent to be used. Illustrative examples of
crosslinking initiators include, but are not limited to, potassium
persulfate, azobisisobutyronitrile, and benzyl dimethyl ketal
(BDK).
The dispersing agent may assist in uniform distribution of the
constituents within the composition. Generally, the dispersing
agent may be C.sub.15-38 alkanes, C.sub.15-38 esters, C.sub.15-38
organic acids, and mixtures thereof. In the examples presented
hereinafter, the dispersing agent used is paraffin.
According to various embodiments of the present invention, the
weight percent of the dispersing agent of the composition for
preparing a non-dripping flame retarding masterbatch is about 0.1%
to about 1.5%. Specifically, the weight percent of the dispersing
agent of the total composition may be about 0.1, 0.2, 0.3, 0.4,
0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, or 1.5%.
Any synthetic thermoplastic polymer may be used according to the
embodiments of the present invention; particularly those suitable
for spinning process. Examples of the thermoplastic polymer may
include, but are not limited to, polyester, polyamide,
polypropylene (PP) and polyvinyl chloride (PVC).
Specifically, illustrative examples of polyester may include
polyethylene terephthalate (PET), polybutylene terephthalate (PBT),
and polytrimethylene terephthalate (PTT). Polyamide is a synthetic
polymer family including, but not limited to, nylon 6, nylon 6.6
and nylon 6.10.
The weight percent of the thermoplastic polymer of the total
composition is about 76.5% to about 99.5%. In some embodiments, the
thermoplastic polymer is in an amount of about 79-94 wt %.
Specifically, the weight percent of the thermoplastic polymer of
the total composition may be about 76.5, 77, 77.5, 78, 78.5, 79,
79.5, 80, 80.5, 81, 81.5, 82, 82.5, 83, 83.5, 84, 84.5, 85, 85.5,
86, 86.5, 87, 87.5, 88, 88.5, 89, 89.5, 90, 90.5, 91, 91.5, 92,
92.5, 93, 93.5, 94, 94.5, 95, 95.5, 96, 96.5, 97, 97.5, 98, 98.5,
99, or 99.5%.
In another aspect, the present disclosure is directed to a method
for preparing a non-dripping flame retarding masterbatch using the
composition provided in the above-mentioned aspect/embodiments.
According to one embodiment of the present disclosure, the method
comprises the steps as follows. First, about 0.1 to about 15.0 wt %
flame retardant, about 0.1 to about 1.5 wt % crosslinking agent,
about 76.5 to about 99.5 wt % thermoplastic polymer, and about 0.1
to about 5.0 wt % dispersing agent are admixed to form an
admixture. Thereafter, about 0.01 to about 2.0 wt % crosslinking
initiator was added into the admixture to form a composition for
compounding. The composition is compounded to melt the
thermoplastic polymer whereby the melted thermoplastic polymer is
cross-linked by the crosslinking agent, and the retarding agent is
dispersed in the cross-linked thermoplastic. Generally, the
compounding step is performed for about 1-20 minutes, and a
compounding temperature is about 220-270.degree. C. Afterwards, the
cross-linked thermoplastic having the retarding agent dispersed
therein is pelletized to obtain the non-dripping flame retarding
masterbatch.
The compounding and pelletizing steps are carried out in the
extruder. Any customary extruders and extrusion techniques for
preparing masterbatches may be employed according to the
embodiments of the present invention. A well-known compounding
apparatus may include, but is not limited to, a twin screw
extruder. During the operation of the twin screw extruder, the
process parameters may be adjusted depending on the actual
situation. For example, in one optional embodiment, the speed of
the screw member may be adjusted to about 250-350 rpm.
In some embodiments, the mixing steps may be carried out in any
suitable container or mixer. Thereafter, the composition is fed
into an extruder for compounding and/or pelletizing the
masterbatch. Alternatively, the mixing steps may be done in the
extruder.
In one optional embodiment, the pelletized non-dripping flame
retarding masterbatch may be treated by a UV curing process. The UV
curing process may further improve the thermal resistance and
non-dripping efficacy of the non-dripping flame retarding
masterbatch and/or the final product.
Some working examples according to embodiments of the present
invention are provided hereinafter. Compositions used in each
working examples (Examples A2-A3, B2-B3, E2-E3) and comparative
examples (Examples A1, B1, C1, D1, E1) and test results thereof are
summarized in Table 1 and Table 2. Examples in Table 1 used nylon 6
as the thermoplastic polymer; while examples in Table 2 used
polyester as the thermoplastic polymer. Working examples listed in
Table 1 and Table 2 comprised paraffin in an amount of about 0.5 wt
% as the dispersing agent and BDK in an amount of about 0.05 wt %
as the crosslinking initiator. In addition, polyphosphate (as flame
retardant) and TAIC (as crosslinking agent) were used in various
amounts in the examples. No crosslinking initiator is used in the
comparative examples.
Also, some of the non-dripping flame retarding masterbatches were
further treated by a UV curing process to improve the thermal
resistant and non-dripping properties thereof. Masterbatches of the
comparative examples did not treated by the UV curing process,
since there was no crosslinking agent present in the
composition.
The masterbatches of the examples were further spun into fibers,
and the limited oxygen index (LOI) of each fiber was measured.
TABLE-US-00001 TABLE 1 Flame LOI LOI retardant Crosslinking Nylon 6
without with (wt %) agent (wt %) (wt %) UV curing UV curing A1 5.0
0 94.5 20 -- A2 5.0 0.6 93.85 21 23 A3 5.0 1.5 92.95 21 25 B1 10.0
0 89.5 24 -- B2 10.0 0.6 88.85 25 28 B3 10.0 1.5 87.95 26 31 C1
15.0 0 84.5 28 -- C2 15.0 0.6 83.85 26 30 C3 15.0 1.5 82.95 27 33
D1 30 0 79.45 32 --
TABLE-US-00002 TABLE 2 Flame LOI LOI retardant Crosslinking
Polyester without with (wt %) agent (wt %) (wt %) UV curing UV
curing E1 15 0 84.5 23 22 E2 15 0.5 83.95 24 25 E3 15 1.5 82.95 26
28
Take working example B3 as an example, the method for preparing the
non-dripping flame retarding masterbatch comprises the steps as
follows. First, about 10.0 wt % polyphosphate, about 1.5 wt % TAIC,
about 87.95 wt % nylon 6, and about 0.5 wt % dispersing agent were
admixed to form an admixture. Then, to the admixture was added BDK
in an amount of about 0.05 wt % to form a composition. The
composition was compounded for about 20 minutes at a compounding
temperature of about 220-270.degree. C. During the compounding
step, the nylon 6 was melted by heat and crosslinked under the
action of TAIC, while the polyphosphate evenly dispersed within the
crosslinked nylon 6 molecules. After the compounding step, the
compounded product was pelletized so as to produce the non-dripping
flame retarding masterbatch of working example B3. Masterbatches of
other working examples and comparative examples are prepared by
similar process except the composition and/or weight ratio of the
constituents were modified as specified in Table 1 and Table 2.
The masterbatch was dried at about 85.degree. C. in a baking oven.
In the case where the masterbatch was treated by the UV curing
process, the dried masterbatch was irradiated by a UV lamp for
about 1-60 minutes.
The dried masterbatch, with or without UV curing treatment, was
spun into fiber, and the LOI value of the fiber was measured in
accordance with the procedure set forth in ASTM standard D2863-00.
LOI is used to represent the relative flammability of plastics and
other materials. In brief, the principle of the LOI test is to
measure the minimum concentration of oxygen (i.e., LOI) that will
just support flaming combustion of a material in a controlled
oxygen/nitrogen mixture environment. Generally, higher LOI value
represents better flame retarding efficacy. In the related field, a
material with an LOI.gtoreq.20 is classified as flame retarding.
However, in actual application, a flame retarding fiber must have
an LOI.gtoreq.26 (nonflammable grade) so as to exhibit acceptable
fire retarding efficacy. A fiber with an LOI of 26 would start
burning upon contacting with the flame, but the burning may go out
as soon as the fiber leaves the flame and the fiber may get
carbonized during the burning.
As can be observed from the data shown in Table 1 and Table 2,
while the amount of the flame retardant was kept constant, the
addition of a substantially small amount (0.5 wt % of the total
composition) of crosslinking agent is sufficient to increase the
LOI value of the fiber.
Examples listed in Table 1 used polyamide (nylon 6) as the
thermoplastic polymer. Take comparative example A1 and working
example A2 for example, the addition of about 0.6 wt % crosslinking
agent may increase the LOI value (without curing) from 20 to 21.
Similar results may also be observed in other examples, such as
comparative example B1 comparing to working example B2 and
comparative example C1 comparing to working example C2.
Moreover, as the amount of the crosslinking agent increases, the
LOI value of the fiber also increases correspondingly. For example,
in the working example C2, the amount of the crosslinking agent
thereof is about 6 wt %, and the LOI value (without UV curing)
thereof is 26, while in the working example C3, the amount of the
crosslinking agent thereof is about 1.5 wt %, and the LOI value
(without UV curing) thereof is 27.
Examples listed in Table 2 used polyester as the thermoplastic
polymer. By comparing the comparative example E1 to the working
example E2, it is observed that the addition of a small amount (0.5
wt % of the total composition) may increase the LOI value (without
UV curing) from 23 to 24.
Furthermore, as can be seen from Table 1 and Table 2, the
non-dripping flame retarding masterbatch of the present disclosure,
though comprising less amount of flame retardant (about 0.1-15 wt
%) comparing to the commercial products (comprising flame retardant
of 20-30 wt %), exhibits satisfactory flame retarding efficacy,
especially those being treated by the UV curing process.
More specifically, in working examples B2, B3, C2, and C3, only 10
wt % or 15 wt % were used; nevertheless, the LOI values of these
working examples with UV curing process are respectively 28, 31,
30, and 33, all which are qualified as the nonflammable grade
(LOI.gtoreq.26). Similarly, working example E3 comprised about 15
wt % flame retardant, and its LOI with and without UV curing
treatment are 28 and 26, respectively. Thus, the E3 fiber is also
nonflammable.
Moreover, comparative example D1 comprised about 30 wt % flame
retarding which is much higher than that of working example C3
(with 15 wt % flame retardant); however, the LOI value of
comparative example D1 (32) is lower than that of the UV-cured
working example C3 (33).
Currently, there is no widely accepted standard for testing the
dripping property of the fibers and textiles. In the present
disclosure, UL 94 vertical combustion test, which is directed to
the combustion behaviors of engineering plastics, was carried out
to observe the dripping property of the sample.
The test results show that the chips made of the non-dripping flame
retarding masterbatch of the present disclosure may qualify as the
V1 level to V0 level (non-dripping during combustion).
FIG. 1A and FIG. 1B are photos illustrating the after-burnt
appearance of a pure nylon chip (FIG. 1A) and the chip of working
example B3 (FIG. 1B). In FIG. 1A, significant dripping can be
observed (the dropping on the surface of the chip is the dripping).
In comparison, a char (carbonized layer) was formed on the surface
of the chip of working example B3 (FIG. 1B) whereby preventing the
formation of the dripping.
Similar results were obtained regarding polyester materials.
After-burnt appearances of a pure polyester chip and a chip of
working example E3 are presented in FIG. 2A and FIG. 2B,
respectively. In FIG. 2A, significant dripping can be observed. In
comparison, a char was formed on the surface of the chip of working
example E3 (FIG. 2B) whereby preventing the formation of the
dripping.
In yet another aspect, the present disclosure is directed to a
non-dripping flame retarding material. In various embodiments, the
flame retarding material can be manufactured in a form of a
masterbatch, a fiber, a filament, a yarn, a textile, a film, a
sheet, or a chip.
According to embodiments of the present disclosure, the
non-dripping flame retarding material comprises a crosslinked
thermoplastic polymer and a fire retardant dispersed within the
crosslinked thermoplastic polymer, wherein the weight ratio of the
crosslinked thermoplastic polymer to the fire retardant is about
5:1 to 996:1. In this regard, the weight of crosslinked
thermoplastic polymer is the sum of the amount of the crosslinking
agent and the amount of the thermoplastic polymer used in the
composition for making this non-dripping flame retarding
material.
In some optional embodiments, the weight ratio of the crosslinked
thermoplastic polymer to the fire retardant is about 5.5:1 to 19:1.
Specifically, the weight ratio may be 5.5:1, 6:1, 7:1, 8:1, 9:1,
10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1 or 19:1. For
example, according to the above-mentioned working examples E2 and
E3, the sum of the weight percents of the crosslinking agent and
the thermoplastic polymer is about 84.45%, while the weight percent
of the fire retardant is about 15%; therefore, the weight ratio of
the crosslinked thermoplastic polymer to the fire retardant is
about 5.63:1 (.about.5.5:1). According to working examples A2 and
A3, the weight ratio of the crosslinked thermoplastic polymer
(94.45 wt %) to the fire retardant (5 wt %) is about 18.89:1
(.about.19:1).
According to the principle and spirit of the present disclosure,
the non-dripping flame retarding material is at least partially
made of/from the non-dripping flame retarding masterbatch disclosed
herein. Hence, the constituents making up the composition and
weight ratios thereof are disclosed in the above-described
embodiments. Accordingly, for the sake of brevity, a description of
the composition for preparing the non-dripping flame retarding
material is not repeated.
According to the principle and spirit of the present disclosure,
the non-dripping flame retarding masterbatch is suitable for use in
a spinning process. Moreover, the masterbatch can be spun directly
without adding additional pure thermoplastic masterbatch. A
simulation analysis was conducted to determine the pressure rise of
the present masterbatch so as to evaluate the spinnability of the
masterbatch.
The result of the analysis shows that the pressure rise of the E1
masterbatch may increase 5 folds during the spinning process. In
this case, the pressure is so high that it may cause damage to the
spinning apparatus. Hence, the E1 masterbatch is not suitable for
the spinning process.
In comparison, a relatively stable spinning pressure is observed in
the simulation analysis of the masterbatch E3. Specifically, the
pressure variation of masterbatch E3 during the spinning process is
no greater than 5 bars. Hence, the masterbatch according to the
present disclosure exhibits satisfactory spinnability.
In addition, Textechno FPAC Strength Tester (Serial No. 35032) was
used to determine the mechanical properties of the fibers made from
the masterbatches of various working examples.
First, B3 masterbatch was spun into fibers with various linear
densities, as shown in Table 3. The fibers were tested according to
the protocol provided with the strength tester, and the tenacity
and elongation data thus obtained are summarized in Table 3.
Generally, fibers with desirable tenacity are suitable for
subsequent process for forming the yarns; moreover, such
fibers/yarns are suitable to be used in the machine for knitting or
plain weaving. Elongation of a fiber is related to the
extensibility of the fiber during the spinning process. Usually, a
fiber with an elongation rate less than 30% may break during the
subsequent process such as draw-spinning.
As shown in Table 3, in working example B3-1, the fiber was spun
under a condition where the speeds of the first and third screw are
about 500 and 600 rpm, respectively, and thus, an extension ratio
of the screws was 1:1.2 (500:600). Still refer to Table 3, the
fiber of working example B3-6 was spun under a condition where the
speeds of the first and third screw are about 600 and 2100 M/min,
and thus an extension ratio of the screws was 1:3.5 (600:2100).
Accordingly, the tenacity of the fiber of working example B3-6
(2.09 g/den) is higher than that of the fiber of working example
B3-1 (0.81 g/den).
Furthermore, the fiber of working example B3-6 exhibit an
elongation greater than 45%, which makes the fiber suitable for
draw-spinning.
TABLE-US-00003 TABLE 3 Screw speed Fiber Linear Tenacity M/min
Density (den) (g/den) Elongation (%) B3-1 500-600 215 0.81 263.55
B3-2 500-700 220 0.96 193.81 B3-3 500-1000 168.3 1.32 133.05 B3-4
500-1250 132.2 1.66 84.99 B3-5 500-1400 147.6 1.83 56.21 B3-6
600-2100 131.2 2.09 47.33
Further analysis regarding fibers of other working examples shows
that when the composition for preparing the masterbatch comprises a
about 8 wt % flame retardant, the fiber thus-obtained has a
tenacity of about 2.6 g/den, and an elongation of about 6.97%.
Moreover, when the amount of the flame retardant is increased to
about 12.0 wt %, the tenacity and elongation of the resultant fiber
are about 2.1 g/den and about 47.33%, respectively.
In comparison, when the composition for preparing the masterbatch
comprises about 20 wt % flame retardant, it is unable to spin the
resultant masterbatch because the pressure rise simulation show
that the pressure rise during the spinning process is unstable.
The fibers of the working examples were further knitted into
fabrics. Photos illustrating appearances of the fabric made of the
fibers of working example B3-5 before and after burning are
presented in FIG. 4A and FIG. 4B, respectively. As can be seen in
FIG. 4B, char was formed on the fabric and no dripping was produced
upon burning.
Textiles/fabrics will usually go through dyeing and finishing
process. Such process(s) may sometimes jeopardize the functionality
of the final product. Hence, washing fastness of the fabrics of the
present disclosure was determined according to the procedure set
forth in AATCC 61-2008 standard.
The fiber of working example B2 was processed into a plain-woven
fabric and dyed with the testing dye. During the dyeing process,
the dyeing system was heated from room temperature (about
23-27.degree. C.) to about 100.degree. C. at a rate of about
2.degree. C./min and maintained at about 100.degree. C. for about
30 minutes; then, the dyeing system was cool to about 75.degree. C.
at a rate of about 2.degree. C./min and maintained at 75.degree. C.
for 15 minutes so that the color can be fixed onto the fabric. Test
results showed that the dyed fabric had a washing fastness of at
least level 4.5, which is acceptable by the textile field.
Furthermore, the LOI test was conducted to determine the
flammability of the dyed fabric. The LOI value of the dyed fabric
made from the fiber of working example B2 is 27, which belongs to
the nonflammable grade.
It will be understood that the above description of embodiments is
given by way of example only and that various modifications may be
made by those with ordinary skill in the art. The above
specification, examples and data provide a complete description of
the structure and use of exemplary embodiments of the invention.
Although various embodiments of the invention have been described
above with a certain degree of particularity, or with reference to
one or more individual embodiments, those with ordinary skill in
the art could make numerous alterations to the disclosed
embodiments without departing from the spirit or scope of this
invention.
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